Tick-Induced Mammalian Meat Allergy in Australia

National Prevalence and Geographic Distribution from Laboratory Surveillance, 2014-2024

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Authors

Emily Smith1,2, Paul Campbell3, Carl Kennedy4, Karl Baumgart5, Lucinda Williams6, Sheryl van Nunen7,8,9,10, Andrew Walker1, and Alexander W. Gofton2,10,*

Affiliations

1 University of Queensland, Brisbane, Australia

2 CSIRO Health and Biosecurity, Brisbane, Australia

3 QML Pathology, Brisbane, Australia

4 Sullivan Nicolaides Pathology, Brisbane, Australia

5 Douglas Hanley Moir Pathology, Sydney, Australia

6 Laverty Pathology, Sydney, Australia

7 Northern Beaches Hospital, Sydney, Australia

8 National Allergy Centre of Excellence, Australia

9 The University of Sydney, Sydney, Australia

10 TiARA (Tick-induced Allergies Research and Awareness), Australia

  • Correspondence to Alexander W. Gofton; alexander.gofton@csiro.au

Published Manuscript

Link to published manuscript

Abstract

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About This Interactive Application

This interactive web application provides access to the data visualizations and analyses presented in the Tick-Induced Mammalian Meat Allergy in Australia: National Prevalence and Geographic Distribution from Laboratory Surveillance, 2014-2024 (PUBLICATION DETAILS).

Users can explore:

  • Interactive Map (Figuer 6): Explore geographic distribution of suspected MMA cases across Australia
  • Figures 1-7: Interactive versions of all manuscript figures with zoom and exploration capabilities
  • Data tables and detailed regional statistics

Navigate through the sections below to explore different aspects of the analysis. All figures are interactive and can be zoomed and panned for detailed examination.

Data Sources

Deidentified data were obtained from all a-Gal sIgE immunoCAP™ tests submitted to the following pathology service providers between January 1 2014, and December 31 2024:

These laboratories provide services across all Australian states and territories and conduct the majority of a‑Gal sIgE testing in Australia, although the exact proportion of total testing conducted by these providers is unknown. Data contained a unique deidentified patient, a unique test identifier, patient year of birth, sex, and residential postcode, date of test, and the test result in kilounits of a-Gal sIgE (kU/L). Clinical records, travel histories, and other information were not obtained.


© 2025 | For questions or feedback, please contact: alexander.gofton@csiro.au

Interactive Map

Figure 6 (interactive version) Geographic distribution of suspected mammalian meat allergy cases per 1 million population per year (1M PPY) in Australia 2014-2024. Red line indicated the approximate western edge of the distribution of the causative tick Ixodes holocyclus.

Data Table

Figure 1. Age and Sex Distribution

Figure 1 Age distribution by sex of all tested people (A) and people with suspected MMA (B).

Figure 1 Age distribution by sex of all tested people (A) and people with suspected MMA (B).

Figure 2. Risk Ratios

Figure 2 Risk ratios comparing: (A) males to females within each age category, (B) each age group to the reference (25–34 years, pooled sexes), and (C) all age-sex combinations to females aged 25–34 years (the lowest-risk group, 18.5% positivity). Filled circles indicate statistical significance (p < 0.01); open circles indicate non-significant comparisons. Error bars represent 95% confidence intervals. Dashed vertical line indicates RR = 1.0 (no difference from reference group).

Figure 2 Risk ratios comparing: (A) males to females within each age category, (B) each age group to the reference (25–34 years, pooled sexes), and (C) all age-sex combinations to females aged 25–34 years (the lowest-risk group, 18.5% positivity). Filled circles indicate statistical significance (p < 0.01); open circles indicate non-significant comparisons. Error bars represent 95% confidence intervals. Dashed vertical line indicates RR = 1.0 (no difference from reference group).

Figure 2 Risk ratios comparing: (A) males to females within each age category, (B) each age group to the reference (25–34 years, pooled sexes), and (C) all age-sex combinations to females aged 25–34 years (the lowest-risk group, 18.5% positivity). Filled circles indicate statistical significance (p < 0.01); open circles indicate non-significant comparisons. Error bars represent 95% confidence intervals. Dashed vertical line indicates RR = 1.0 (no difference from reference group).

Figure 4. Testing Expansion

Figure 4 Dual expansion of α-Gal sIgE testing infrastructure in Australia, 2014-2024. (A) Geographic expansion: number of SA3 regions conducting testing; shaded area shows CI. (B) Testing intensity: mean tests per region; error bars show standard error. (C) Relative contributions of geographic expansion and testing intensity to overall testing volume growth. (D) Heterogeneity in regional testing intensity changes; violin plot shows probability density, boxplot indicates median (66.7%) and interquartile range (0-200%), and individual points represent SA3 regions. (E) Heatmap showing annual testing volume for the 50 SA3 regions with highest total test numbers from 2014-2024 in descending order.

Figure 4 Dual expansion of α-Gal sIgE testing infrastructure in Australia, 2014-2024. (A) Geographic expansion: number of SA3 regions conducting testing; shaded area shows CI. (B) Testing intensity: mean tests per region; error bars show standard error. (C) Relative contributions of geographic expansion and testing intensity to overall testing volume growth. (D) Heterogeneity in regional testing intensity changes; violin plot shows probability density, boxplot indicates median (66.7%) and interquartile range (0-200%), and individual points represent SA3 regions. (E) Heatmap showing annual testing volume for the 50 SA3 regions with highest total test numbers from 2014-2024 in descending order.

Figure 4 Dual expansion of α-Gal sIgE testing infrastructure in Australia, 2014-2024. (A) Geographic expansion: number of SA3 regions conducting testing; shaded area shows CI. (B) Testing intensity: mean tests per region; error bars show standard error. (C) Relative contributions of geographic expansion and testing intensity to overall testing volume growth. (D) Heterogeneity in regional testing intensity changes; violin plot shows probability density, boxplot indicates median (66.7%) and interquartile range (0-200%), and individual points represent SA3 regions. (E) Heatmap showing annual testing volume for the 50 SA3 regions with highest total test numbers from 2014-2024 in descending order.

Figure 4 Dual expansion of α-Gal sIgE testing infrastructure in Australia, 2014-2024. (A) Geographic expansion: number of SA3 regions conducting testing; shaded area shows CI. (B) Testing intensity: mean tests per region; error bars show standard error. (C) Relative contributions of geographic expansion and testing intensity to overall testing volume growth. (D) Heterogeneity in regional testing intensity changes; violin plot shows probability density, boxplot indicates median (66.7%) and interquartile range (0-200%), and individual points represent SA3 regions. (E) Heatmap showing annual testing volume for the 50 SA3 regions with highest total test numbers from 2014-2024 in descending order.

Figure 4 Dual expansion of α-Gal sIgE testing infrastructure in Australia, 2014-2024. (A) Geographic expansion: number of SA3 regions conducting testing; shaded area shows CI. (B) Testing intensity: mean tests per region; error bars show standard error. (C) Relative contributions of geographic expansion and testing intensity to overall testing volume growth. (D) Heterogeneity in regional testing intensity changes; violin plot shows probability density, boxplot indicates median (66.7%) and interquartile range (0-200%), and individual points represent SA3 regions. (E) Heatmap showing annual testing volume for the 50 SA3 regions with highest total test numbers from 2014-2024 in descending order.

Figure 6. Geographic concentration

Figure 5 Geographic concentration of suspected alpha-gal syndrome cases across Australian SA3 regions. (A) Lorenz curve showing cumulative distribution of cases across SA3 regions (ranked by case burden). The diagonal dashed line represents perfect equality; deviation from this line indicates concentration. (B) Pareto chart showing the proportion of total cases accounted for by cumulative percentages of SA3 regions.

Figure 5 Geographic concentration of suspected alpha-gal syndrome cases across Australian SA3 regions. (A) Lorenz curve showing cumulative distribution of cases across SA3 regions (ranked by case burden). The diagonal dashed line represents perfect equality; deviation from this line indicates concentration. (B) Pareto chart showing the proportion of total cases accounted for by cumulative percentages of SA3 regions.

Figure 6. Maps

See Interactive Map

Figure 7. Alpha-Gal sIgE levels reduce over time

Figure 7 Longitudinal changes in α-Gal sIgE levels in people who had > 2 tests. (A) Distribution of individual people’s annual rate of change (beta) of α-Gal sIgE/year from mixed-effects models. Negative values indicate declining antibody levels over time. Dotted line indicates no change; dashed line indicates the median rate of change across the cohort (-0.28 log α-Gal sIgE kU/L). (B) Distribution of individual people’s percentage change in α-Gal sIgE over time compared to their first test. Dotted line indicates no change; dashed line indicates the median percentage change across the cohort (-24.3%). (C) Patients’ first test α-Gal sIgE levels (log-transformed) vs. their individual annual rate of change. Blue points (rate of decline = < 0) indicates patients whose α-gal sIgE levels decreased over time; teal points above indicate increases. The red line shows the linear regression fit with 95% confidence interval (shaded area). The vertical dotted line indicates the seropositivity threshold (0.1 kU/L, and the horizontal dashed line indicates no change (slope = 0). (D) Scatter plot comparing first and last α-gal sIgE measurements (log-transformed) for each person. Blue points below the diagonal long-dashed line (slope = 1) indicates patients whose α-gal sIgE levels decreased between first and last test; teal points above indicate increases. The red line shows linear regression fit with 95% confidence interval. The positive threshold of 0.1 kU/L alpha-gal sIgE is marked with dotted lines on both axes.

Figure 7 Longitudinal changes in α-Gal sIgE levels in people who had > 2 tests. (A) Distribution of individual people’s annual rate of change (beta) of α-Gal sIgE/year from mixed-effects models. Negative values indicate declining antibody levels over time. Dotted line indicates no change; dashed line indicates the median rate of change across the cohort (-0.28 log α-Gal sIgE kU/L). (B) Distribution of individual people’s percentage change in α-Gal sIgE over time compared to their first test. Dotted line indicates no change; dashed line indicates the median percentage change across the cohort (-24.3%). (C) Patients’ first test α-Gal sIgE levels (log-transformed) vs. their individual annual rate of change. Blue points (rate of decline = < 0) indicates patients whose α-gal sIgE levels decreased over time; teal points above indicate increases. The red line shows the linear regression fit with 95% confidence interval (shaded area). The vertical dotted line indicates the seropositivity threshold (0.1 kU/L, and the horizontal dashed line indicates no change (slope = 0). (D) Scatter plot comparing first and last α-gal sIgE measurements (log-transformed) for each person. Blue points below the diagonal long-dashed line (slope = 1) indicates patients whose α-gal sIgE levels decreased between first and last test; teal points above indicate increases. The red line shows linear regression fit with 95% confidence interval. The positive threshold of 0.1 kU/L alpha-gal sIgE is marked with dotted lines on both axes.

Figure 7 Longitudinal changes in α-Gal sIgE levels in people who had > 2 tests. (A) Distribution of individual people’s annual rate of change (beta) of α-Gal sIgE/year from mixed-effects models. Negative values indicate declining antibody levels over time. Dotted line indicates no change; dashed line indicates the median rate of change across the cohort (-0.28 log α-Gal sIgE kU/L). (B) Distribution of individual people’s percentage change in α-Gal sIgE over time compared to their first test. Dotted line indicates no change; dashed line indicates the median percentage change across the cohort (-24.3%). (C) Patients’ first test α-Gal sIgE levels (log-transformed) vs. their individual annual rate of change. Blue points (rate of decline = < 0) indicates patients whose α-gal sIgE levels decreased over time; teal points above indicate increases. The red line shows the linear regression fit with 95% confidence interval (shaded area). The vertical dotted line indicates the seropositivity threshold (0.1 kU/L, and the horizontal dashed line indicates no change (slope = 0). (D) Scatter plot comparing first and last α-gal sIgE measurements (log-transformed) for each person. Blue points below the diagonal long-dashed line (slope = 1) indicates patients whose α-gal sIgE levels decreased between first and last test; teal points above indicate increases. The red line shows linear regression fit with 95% confidence interval. The positive threshold of 0.1 kU/L alpha-gal sIgE is marked with dotted lines on both axes.

Figure 7 Longitudinal changes in α-Gal sIgE levels in people who had > 2 tests. (A) Distribution of individual people’s annual rate of change (beta) of α-Gal sIgE/year from mixed-effects models. Negative values indicate declining antibody levels over time. Dotted line indicates no change; dashed line indicates the median rate of change across the cohort (-0.28 log α-Gal sIgE kU/L). (B) Distribution of individual people’s percentage change in α-Gal sIgE over time compared to their first test. Dotted line indicates no change; dashed line indicates the median percentage change across the cohort (-24.3%). (C) Patients’ first test α-Gal sIgE levels (log-transformed) vs. their individual annual rate of change. Blue points (rate of decline = < 0) indicates patients whose α-gal sIgE levels decreased over time; teal points above indicate increases. The red line shows the linear regression fit with 95% confidence interval (shaded area). The vertical dotted line indicates the seropositivity threshold (0.1 kU/L, and the horizontal dashed line indicates no change (slope = 0). (D) Scatter plot comparing first and last α-gal sIgE measurements (log-transformed) for each person. Blue points below the diagonal long-dashed line (slope = 1) indicates patients whose α-gal sIgE levels decreased between first and last test; teal points above indicate increases. The red line shows linear regression fit with 95% confidence interval. The positive threshold of 0.1 kU/L alpha-gal sIgE is marked with dotted lines on both axes.